Process and apparatus for the extraction op g-lxte



F. H. TUNNELL, PROCESS AND APPARATUS FOR THE 'EXTRACTION 0F GLUE, GELATIN, AND THE LIKE. APPLICATION-{FILED JUNE 28I 1919.

1,364,904, Pdtnted Jan. 11,1921.

-.,Y.. a v 37 INVENTOR fizecieir/b lane/Z A TTORNEYS UNITED STATES PATENT OFFICE.

FREDERIC H. TUNNELL, or PHILADELPHIA, PENNSYLVANIA.

PROCESS AND APPARATUS FOR THE EXTRACTION OF GLUE, GELATIN, AND THE LIKE.

Application filed June 28, 1919.

glue, gelatin and the like from the usual materials employed for that purpose and commercially known as glue stock, among the principal objects thereof being to provide a process and apparatus adapted for performing it, by the use of which may be produced glue or gelatin of quality improved in adhesive or binding strength over that obtainable by the means at present employed. Ad-

ditionally, the glue produced by my process is practically free from foam or froth, 6X tremely undesirable attributes of glue produced by the processes hitherto utilized, the same being due to the presence of lime soaps which are left in varying quantities in the glue when manufactured by the said processes. The employment of my process, however, results in the reduction of these lime soaps to a minimum, whereby the foaming and frothing of the finished glue when used commercially is also similarly reduced, while the latter when produced from certain varieties of glue stock by myprocess is of a much better color and transparency than glue produced from similar stock by other methods.

Moreover. the use of my process and apparatus in the extraction of glue results in a greater yield of glue or gelatin from a given weight of any class of glue making material as well as increased economies in manufacture due to the avoidance of the necessity for mechanical agitation during the carrying out of the process and to a distinct saving in the steam or other heating medium employed.

A still further advantage in my process results from the fact that in carrying out the process which is conducted in an open tank, as distinguished from a tank adapted to maintain the contents under greater than atmospheric pressure, it is never necessary Specification of Letters Patent.

Patented Jan. 11, 1921.

Serial No. 307,369.

to raise the temperature of the extracting liquid, or of the solid matter with which it is associated, to the boiling point, as it is found that the process may be most advantageously carried out when the temperature of the extractlng liquid is kept at a point below 212 F.; thus the detrimental effect of hlgh temperatures on the glue solution is avolded, enhancing the quality of the finished product or commercial glue to a marked degree, as hitherto stated.

My invention further includes all of the other var1ous novel steps, features, characteristics, objects and advantages to which reference may hereinafter be made.

In carry ng out my improved process for the extraction of glue, gelatin and the like, I may employ any suitable apparatus, but have found in practice that an apparatus constructed substantially as hereinafter de scribed and shown in the acompanying drawlng, 1n which the said apparatus is illustrated somewhat diagrammatically, Figure 1 showing the same partially in central vertical section and partially in elevation, and Fig. 2 being a fragmentary-hori zontal section taken on the lines 22 of Fig. 1 looking in the direction of the arrows, is well adapted for the purposes intended. However, if desired, other suitable forms of apparatus may be employed for carrying out the processs.

Referring to the drawing, the apparatus shown therein may comprise a suitable tank 1 of metal, wood or other material which may preferably be of circular transverse section with slightly diverging side walls whereby the diameter of the tank is increased toward the top which is left entirely open. The tank may be supported on suitable beams or other flooring 2 in any convenlent way, and provided with a steam coil 3 located adjacent the bottom 4 of the tank, to which steam may be supplied by a steam pipe 5 controlled by a valve 6. The coil may be of any suitable or desired construction either entirely closed, or else provided with perforations 8 as shown. It is found in practice, however, that substantially equally good results are obtained through the use of a closed coil effective to heat the contents of the tank by radiation alone as by the use of a perforated coil effective to heat by radiation supplemented by jets of live steam liberated into the contents of the tank. The tank may also be provided with a suitable liquid gage 10 whereby the height of the liquid in the tank may be easily determined by observation, and also with an out-let pipe 12 communicating with the interior of the tank through the bottom, and preferably passing downwardly therefrom, thence in a horizontal direction and thence vertically upward to a suitable height above the floor 2, where it is curved over and arranged to discharge into a tunnel or hopper 13, the end oi the pipe terminating a short distance above the mouth of the hopper so that the liquid flowing from the pipe may be readily observed by the operator oi the apparatus. From the hopper 13 the pipe 14L is arranged to lead the discharged liquid to any desired point in preparation tor such further treatment as may be desired, which treatment forms no part of the present invention. For rcgulating the flow of glue solution from the tank, the pipe 12 may be provided with a suitable conveniently positioned valve 15, and to facilitate continuous testing of the solution a suitable test tube 17 may be located above the valve, or in any other suitable position, connected with pipe 12 by smaller pipes 18, and supplied with a hydrometer 20, the parts being arranged in such manner that as the glue solution flows through the pipe 12 a part of it will. be by-passed through pipes 18 into the test tube 17, where its density may be conveniently ascertained. A large drain pipe 21 provided with a valve 22 may also be provided for draining the tank.

Positioned within the tank 1 and at a suitable distance above the bottom 4 thereot, is a preferably circular :talse floor 25 conveniently supported on beams or posts 26 so as to afford a space or chamber 27 be tween the bottom t and the under side of the false floor 25, which is provided with a plurality of suitable holes or apertures 28 and, preferably at its center, with a vertically positioned stand pipe 30 of sufficient length to extend above the top of the tank for a suitable dis ancc. This pipe may be of any convenient diameter, is preferably considerably enlarged adjacent its lower end, for a height of several inches as clearly shown in Fig. l, and is provided with a flange 33 which may be conveniently secure l as by bolts or nuts 3 35 to the false floor 25, in which is formed. an opening 38 corresponding with the opening in the end of the pipe. A valve lf) may be located in the pipe above the top of the tank, and beyond the valve a plurality of. holes or apertures it]. are drilled or otherwise Iormed in the walls of the pipe preferably substan lly normal to its axis, the upper end of the pipe being closed and provided with a clown- Wardly curved, preferably circular bafile plate 42 of a size and shape suitable for deflecting liquid issuing from the apertures 41 and distributing the same over the surface of the contents of the tank.

The false floor 25 may preferably be of a somewhat less diameter than the interior of the tank adjacent thereto, so that an annular opening l5 will be left between the periphery of the floor and the wall of the tank. Suitably secured to the periphery of the former, is a screen 50 of wire netting or other suitable material, the sides of which are inclined upwardly and inwardly so that the netting will present the appearance of a hollow truncated cone, the upper end of which is open and the lower end of which closed by the false floor To assist in holding the netting in position, a plurality oi su} ')orts or battens are prorided and secured to the walls of the tank and to the screen, the battens being wider at the top than at the bottom and positioned vertically and radially in the tank at suitable distances around the interior thereof, as clearly shown in Fig. 2. Th spaces between the battens may preferably be filled before the ank is charged with the material. from which the glue is to be extracted, as hereinafter described, with suitable filtering material 55, and in practice I have found that this material may conveniently consist of excelsior, coke, hair or the like, and in fact, that any cheap material adapted to EU up the spaces between the battens while allowing the glue solution to percolate downwardly therethrough may be conveniently used for this purpose.

My improved process for the extraction of glue, gelatin or the like may be practised by utilizing an apparatus constructed substantially as hereinbefore described either as an intermittent process, in which case the treatment of the glue stock is interrupted when the extracting liquid has acquired a desired dry glue content and all, or a portion, of the extracting liquid withdrawn, 'tresh liquid substituted and the process continued till this liquid reaches a similar con centration, when it is withdrawn and fresh liquid supplied, these operations being repeated until all, or substantially all, oft the colloidal matter in the glue stock is extracted, or the process may be practised as a continuing one, in which the treatment of the glue stock is carried on continuously until all, or substantially all, of the colloidal matter is extracted.

in carrying out the process, the spaces between the battens having been packed'with the excelsior or other material 55 and valves 15 and 22 being closed, the tank may be filled, preferably nearly to its top, with a charge of glue stock which may comprise hides, skins, bones, ossine or other animal refuse capable of yielding the desired colloidal matter, and a sufficient amount of water or other extracting liquid then introduced into the tank to fill the space 27 and preferably to rise for several inches above the false floor 25, the exact amount of Water supplied depending on the nature and quality of the stock. Steam is next introduced to the steam coil 3 with suflicient pressure to heat the water adjacent the coil to a little below the boiling point in a suitable time, for example, in about thirty minutes, and valve 40 being open, the heated water rises in the stand pipe, finds outlet through the holes 41, and with considerable force impinges on the under side of the baffle plate from whence it is deflected back over the surface of the contents of the tank. Thereafter the liquid gradually percolates clownwardly toward the bottom of the tank effecting a gradual lixiviation of the entire contents, and, arriving in chamber 27, is reheated and again ascends pipe 30, whereby a constant circulation of the liquid in the tank is efiected. As the whole mass rises in temperature, the steam pressure in the coil 3 may be correspondingly reduced, sufficient pressure, however, at all times being maintained to insure the circulation of the liquid. The treatment of the glue stock is continued for a suitable period which in practice is found to vary ordinarily from an hour and a half to two hours from the time when the heat is first applied until hydrometer readings of the solution in the tank show the same as containing the desired dry glue content, for example, a dry glue content of approximately 4%. The heat may now be shut off and the liquid contents of the tank drained through pipe 21, or in any other convenient way, fresh water or other extracting liquid supplied to the contents of the tank, the heat again turned on and the glue stock treated a second time in a similar manner, these operations being repeated until all, or substantially all, of the colloidal matter has been extracted, after which the solid residue is removed from the tank and a fresh charge of glue stock introduced. However, it is frequently desirable or convenient to operate the process as a continuous one, in which case, instea d of withdrawing all of the liquid when it shows the desired dry glue content. the valve 15 may be opened to permit only a portion of the solution to pass off from the tank at a moderate speed, determined by the size of the container and the quantity of the contents thereof. It will be found that the dry glue content in the liquid withdrawn from the tank will slowly increase as the treatment of the glue stock is continued, until a point is reached, for example when the solution shows a glue content of say, substantially 6%, when it may be desirable to add more Water to the contents of the tank, which operation may be readily effected by a suitable tap positioned to direct the water into the tank. From this point in the process the amount of water added should preferably approximate the amount of liquid drawn off, due allowance being made for the addition of water from the condensation of live steam if same is supplied from the coil 3. The rates of drawing off of solution and of addition of fresh water may be readily regulated so that the dry glue content of the solution flowing through the pipe 12 will remain substantially constant, for example, at a dry glue content of approximately 6%, and this condition of operation having been obtained, the process may be continued unchanged until it is found by test that the dry glue content in the liquid is falling materially below the desired amount, for example, to approximately 4%. When this condition is reached, no more fresh water should be in-- troduced into the tank, but the heat may preferably be continued to be applied, and the circulation of the liquid contents of the tank kept up, until it is found that no additional glue is being extracted from the solid matter in the tank, after which the steam is shut oli', the liquid contents of the tank withdrawn, and the refuse remaining from the charge removed, all, or substantially all, of the glue or gelatin having been extracted therefrom.

It will be understood that while I have described certain methods of carrying out the process the subject of my invention, the same are only illustrative and may frequently be conveniently modified in various particulars to meet varying conditions, and it will further be noted that in the carrying out of the process, no manual or mechanical agitation of the contents of the tank is re quired or employed, the circulation of the liquid therein induced being suiiicient to effect the extraction of the maximum quantity of glue or gelatin from the glue stock.

It has been found in practice that during the treatment of certain classes of glue stock there is a tendency toward the formation of a relatively impermeable cake at the bottom of the mass, which tends to clog the holes in the false floor, and thereby impede the passage of the liquid However, in an apparatus constructed as. hereinbefore described, a constant and adequate circulatii'm of the liquid is insured. for while a certain amount of the cake may form adjacent the surface of the false floor there seems but little tendency for the cake to form on the surface of the screen 50. while such amounts do form the). i are inunediate v washed off by the downwardly percolating liuuid which is constantly passing" through the screen and thence through the holes and annular opening 45, into the chamber 27. It seems probable that the prevention of the formation of the cake on the screen is largely due to its inclination making it difficult for the cake forming matter to adhere thereto, and further that the filling of excelsior, coke or other material around the screen while presenting a considerable surface for the glue stock to rest upon affords, nevertheless, an infinite number of apertures through which the liquid can percolate, so that even though the cake form somewhat thickly at certain points thereby temporarily diminishing the percolation in that vicinity, there are always other points where it can take place with sufficient freedom to insure a return of enough liquid to chamber 27 through the several passages thereto to keep up a constant circulation in the tank, so long as sufficient heat is applied.

While I have illustrated and described herein one form of apparatus suitable for carrying out my process for the extraction of glue, gelatin and the like, I do not thereby desire or intend to limit myself specifically thereto, as various modifications and changes may be made therein if desired. Furthermore, while I have described with considerable particularity certain methods of performing the process itself, and have given certain examples and percentages by way of illustrating the same, I do not thereby desire or intend to limit or restrict the scope of my invention in any way, as suitable modifications and variations may be made in the steps employed. in carrying out the process, and the same may be practised either as an intermittent or continuous process, and the percentages. hereinbefore given by way of example merely may be varied to adapt the process for use with different kinds of glue or gelatin stock, or for the production of glue, gelatin or the like of different grades or qualities, or to meet the varying conditions encountered in different manufacturing establishments as desired, without departing from the spirit and scope of the invention as defined in the appended claims.

Having thus described my invention, I claim and desire to protect by Letters Patent of the United States:

1. The process of extracting glue, gelatin or the like, which consists in effecting by local heating a cyclic circulation of a glue extracting liquid in intimate contact with a mass of glue yielding material whereby said liquid in a single cycle is raised to a point above said mass, diffused over the surface thereof, allowed to percolate therethrough and returned to said point of diffusion.

2. Theprocess of extracting glue, gelatin or the like, comprising the steps of locally heating a glue extracting liquid in intimate contact with a mass of glue-yielding material to produce a cyclic circulation of said liquid whereby said liquid is caused to ascend a conduit adjacent said material, diffusing said liquid over the upper surfaces of said material, and permitting said liquid to percolate downwardly therethrough to a point adjacent the lower end of said conduit, said heating being continued to maintain said circulation until the liquid contains a desired dry glue content.

3. The process of extracting glue, gelatin or the like from a mass of glue yielding material without mechanical agitation, which comprises the steps of heating a glue extracting liquid in contact with said glue yielding material whereby said liquid is' caused to ascend a conduit adjacent said material, diffusing said liquid over the up per surface of said material, permitting said liquid to percolate downwardly through said material to a point adjacent the lower end of said conduit, and continuing said heating to maintain a cyclic circulation of said liquid until said liquid contains a desired dry glue content.

4-. An apparatus for the extraction of glue, gelatin or the like, comprising an open tank having a perforated false floor spaced from the bottom and sides of said tank, a stand pipe extending from said floor to a point above the top of said tank and having openings and a deflecting means adjacent its upper extremity, means for withdrawing liquid from said tank, heating means between said false floor and the bottom of said tank, and a screen disposed around the peripheral edge of said false floor and inwardly inclined with respect thereto.

5. An apparatus for extracting glue, gelatin or the like, comprising an open tank having a perforated false floor spaced from the bottom and sides thereof, a stand pipe extending upwardly from said false floor having a plurality of openings adjacent its upper extremity, a screen surrounding said floor and filtering means disposed between the interior of said screen and the wall of said tank.

6. An apparatus for the extraction of glue, gelatin or the like, comprising a tank having a false floor spaced from the bottom and sides thereof, a stand pipe of varying diameter extending from said false floor to a point above the top of said tank and having a plurality of openings adjacent its upper extremity a deflector disposed adjacent said openings, an inwardly inclined screen surrounding said false floor, a filtering medium disposed between the exterior of said screen and the interior of said tank, screen supporting means, and heating means disposed beneath said false floor and within said tank.

7. An apparatus for the extraction of glue, gelatin or the like comprising a tank having false foraminous floor spaced from means disposed beneath said false floor and the bcttom and sides thereof, a standpipe Within said tank, and a filtering material extending from said false floor to a point disposed above said false floor.

adjacent the top of said tank, said pipe In Witness whereof I have hereunto set 10 5 being of greater diameter adjacent its lower my hand this 27th day of June, A. D. 1919.

than adjacent its upper extremity, heating FREDERIG H. TUNNELL. 

